Rusbridger, who is 60 years old, will maintain close ties with The Guardian by becoming the new chair of The Scott Trust in 2016, the body that safeguards the editorial future and independence of The Guardian in perpetuity. He will succeed Dame Liz Forgan, whose term as chair ends in 2016.

Forgan said: "Alan has been the outstanding editor of his generation. Fully embracing the opportunities of the digital age, he has built on the best traditions of his distinguished predecessors, transforming the Guardian from a print-only national newspaper into the world's leading quality newspaper website.

"We are delighted that The Scott Trust and the wider Group will continue to benefit from his experience, overseeing the independent body that guarantees the editorial integrity and commercial future of the Guardian."

Appointing Rusbridger's successor is expected to involve a newsroom vote held by the Scott Trust, although the publisher declined to confirm this at time of publication.

Under Rusbridger’s editorship, the Guardian has expanded from a UK-only newspaper to an international, multi-platform media organisation and one of the leading quality newspaper websites in the world.

It was also named Newspaper of the Year at the UK Press Awards for its reporting on government surveillance. Its website, theguardian.com, was also awarded the digital award. In addition, the Guardian’s journalism has, in the past 12 months, been recognised with an Emmy, "The Special Award" at the European Press Prize, a Polk award, the Right Livelihood Award in Sweden, and scoop of the year at the 59th Walkley awards for excellence in journalism

Rusbridger said: "In global journalism, there are a handful of roles that have the capability to redefine our industry. I am privileged to have held one of those roles for 20 years, a period in which successful newspapers have become global content providers, reaching audiences in dramatically new and valuable ways.

"I am honoured to succeed the quite brilliant Liz Forgan as chair of The Scott Trust, preserving the independent editorial values and the long-term financial stability upon which our future depends. We have strong future leaders in place with unparalleled news and digital experience, and I know that our journalism will be in the best possible hands."

Neil Berkett, chairman of Guardian Media Group, said: "Alan has set the standard for journalistic leadership in the digital age. His appointment to lead The Scott Trust coincides with rapidly rising readership, continued innovation and secure finances at the Guardian. His successor will inherit a global media organisation in very strong health and with clear prospects for further growth."

The Scott Trust was created in 1936 to safeguard the journalistic freedom and liberal values of the Guardian. In 2008 it became a limited company, with the same protections for the Guardian enshrined in its constitution. Its core purpose is to secure the financial and editorial independence of the Guardian in perpetuity.

Guardian Media Group’s profits are reinvested to sustain journalism that is free from commercial or political interference, and to uphold a set of values laid down by CP Scott, the Manchester Guardian editor.